Q: Update Mac OS X 10.6.8 Snow Leopard?

What year is it from? Check with: Model Identifier Utility

Whether you upgrade or not depends on whether Snow Leopard fits all your needs or if you need features only available in subsequent upgrades. If you use older PPC-only applications they will not run in Lion or later. Other applications you use may require updating to work with a newer OS. So you need to decide if upgrading is necessary. Should you do so your options are:

Upgrading to Lion

If your computer does not meet the requirements to install Mavericks, it may still meet the requirements to install Lion.

You can purchase Lion at the Online Apple Store. The cost is $19.99 (as it was before) plus tax.  It's a download. You will get an email containing a redemption code that you then use at the Mac App Store to download Lion. Save a copy of that installer to your Downloads folder because the installer deletes itself at the end of the installation.

     Lion System Requirements

       1. Mac computer with an Intel Core 2 Duo, Core i3, Core i5, Core i7,

           or Xeon processor

       2. 2GB of memory

       3. OS X v10.6.6 or later (v10.6.8 recommended)

       4. 7GB of available space

       5. Some features require an Apple ID; terms apply.

Upgrading to Mavericks

You can upgrade to Mavericks from Lion or directly from Snow Leopard. Mavericks can be downloaded from the Mac App Store for FREE.

Upgrading to Mavericks

To upgrade to Mavericks you must have Snow Leopard 10.6.8 or Lion installed. Download Mavericks from the App Store. Sign in using your Apple ID. Mavericks is free. The file is quite large, over 5 GBs, so allow some time to download. It would be preferable to use Ethernet because it is nearly four times faster than wireless.

    OS X Mavericks- System Requirements

      Macs that can be upgraded to OS X Mavericks

         1. iMac (Mid 2007 or newer) - Model Identifier 7,1 or later

         2. MacBook (Late 2008 Aluminum, or Early 2009 or newer) - Model Identifier 5,1 or later

         3. MacBook Pro (Mid/Late 2007 or newer) - Model Identifier 3,1 or later

         4. MacBook Air (Late 2008 or newer) - Model Identifier 2,1 or later

         5. Mac mini (Early 2009 or newer) - Model Identifier 3,1 or later

         6. Mac Pro (Early 2008 or newer) - Model Identifier 3,1 or later

         7. Xserve (Early 2009) - Model Identifier 3,1 or later

To find the model identifier open System Profiler in the Utilities folder. It's displayed in the panel on the right.

     Are my applications compatible?

         See App Compatibility Table - RoaringApps.

You can upgrade all the way to the current release of OS X, which is 10.9 Mavericks. It has several performance improvements and new features. The software you listed should run fine under Mavericks, as long as your version of Office isn't 2004 or earlier.

If you decide to try Mountain Lion or Mavericks, why not install it on an external drive to see how you like it? I find a lot of the user interface changes in the versions after Snow Leopard annoying. Many of them can be fixed, but it is an extra step.

I am keeping Snow Leopard as my primary OS as long as possible. It is wonderfully stable and I greatly prefer the interface. I use Mountain Lion occasionally, and I have Mavericks installed on a guinea pig drive. I'd strongly suggest that you proceed in such a way that you don't leave yourself with no Snow Leopard drive.

With the external drive connected, hold down the "option" key while booting up. This shows a list of all bootable volumes/disks.

Or use the Startup Disk control panel in system prefs.